Theoretical Study of the Thermal Decomposition of 5-Methyl-2-Furanylmethyl Radical.

MedLine Citation:

PMID:
22650318
Owner:
NLM
Status:
Publisher

Abstract/OtherAbstract:

The thermal decomposition of 5-methyl-2-furanylmethyl radical (R1), the most important primary radical formed during the combustion and thermal decomposition of 2,5-dimethylfuran (a promising next-generation biofuel), was studied using CBS-QB3 calculations and master equation(ME)/RRKM modeling. Since very few information is available in the literature, the detailed potential energy surface (PES) was investigated thoroughly. Only the main pathways, having a kinetic influence on the decomposition of R1, were retained in the final ME/RRKM model. Among all the channels studied, the ring opening of 5-methyl-2-furanylmethyl radical, followed by ring enlargement to form cyclohexadienone molecules is predicted to be the easiest decomposition channel of R1. The C6 cyclic species formed can undergo unimolecular reactions to give phenol and in a lesser extent cyclopentadiene and CO. Our calculations predict that these species are important products formed during the pyrolysis of 2,5-dimethylfuran (DMF). Other channels involved in the decomposition of R1 lead directly to the formation of linear and cyclic unsaturated C5 species, and constitute an additional source of cyclopentadiene and CO. High-pressure limit rate constants were computed as well as thermochemical properties for important species. ME/RRKM analysis was performed to probe the influence of pressure on the rate coefficients and pressure dependent rate coefficients were proposed for pressures and temperatures ranging, respectively, from 10-2 bar to 10 bar and 1000 K to 2000 K.